Cracks are a road’s worst enemy. Once a crack forms, water is able to enter the paved surface, and when it expands and contracts with changes in temperature it destroys the road. A group of scientists in South Korea have developed a new self-healing concrete coating that they claim can automatically seal cracks, preventing water from entering the material. The high-tech coating is both inexpensive and environmentally friendly, they say, because it could greatly reduce the need to regularly rebuild roads, bridges, and other concrete structures.

The new self-healing concrete, which is being developed by Korean scientist Chan-Moon Chung and colleagues, has a protective coating that contains microcapsules that are filled with a material that can seal cracks. When cracking occurs, the microcapsules are ruptured, and the sealant is released. When sunlight hits the material it becomes solidified, completing the process. The new material promises to reduce the need to frequently repave roads, which is costly for cities and comes at a great environmental expense.

“Although several reports of self-healing anticorrosive coatings for metal protection have appeared, there have been no reports on self-healing protective coating for concrete,” the scientists said in a release. “Our self-healing coating is the first example of capsule-type photo-induced self-healing system, and offers the advantages of catalyst-free, environment-friendly, inexpensive, practical healing,” says the report.